How to sign a Word document on iPhone

Someone sent you a .docx — an offer letter, a rental agreement, a consent form — and it needs your signature. On an iPhone this is a little more awkward than signing a PDF, because a Word document is editable: text reflows, and a signature dropped into it can shift when the sender opens it on a different device.

Here’s the honest version of your options, and the one thing worth knowing before you pick.

First: should you sign the .docx at all?

Usually no — you should turn it into a PDF and sign that instead. A PDF is a fixed, flattened page: what you see is exactly what the sender sees, and your signature can’t drift out of place. A signature sitting inside a live Word file can move if the document is edited or opened in a different version of Word.

So the two real routes are:

Insert a signature image directly in Word (fine for quick, low-stakes documents).
Export the Word doc to PDF, then sign the PDF (better for anything you’re sending back).

Option 1: Insert a signature image in Word for iOS (free)

If you have the Microsoft Word app and the document is casual, you can drop a signature picture straight in:

Make a transparent signature image first — a plain photo of paper leaves an ugly white box around it. The free signature generator draws or types your signature and downloads a transparent PNG in seconds (nothing uploaded). More on why transparency matters: transparent signature PNG.
In Word, tap where the signature goes → Insert → Pictures → pick your PNG.
Resize it and position it over the signature line. Type the date next to it if needed.

Where this is enough: a quick internal form, something informal, a document that isn’t going anywhere official. It’s free and stays inside the app you already have.

Where it gets fiddly, honestly: positioning an image in Word on a phone screen is finicky, the signature can nudge out of place when the file is reopened, and there’s no clean way to add initials on every page. For anything you’re returning to a landlord, HR, or a client, Option 2 is the safer habit.

Option 2: Convert to PDF, then sign it

This is the route worth building into muscle memory. Convert once, sign cleanly, send back.

Export the Word doc to PDF:

In the Word app: tap the ⋯ menu → Export → PDF, or Print → pinch-out on the preview to open it as a PDF.
With Pages: open the .docx, tap ⋯ → Export → PDF.
Working in Google Docs instead? Same idea, different menu — see how to sign a Google Doc on iPhone.
From Files: long-press the .docx, and on newer iOS you can also use Print → share as PDF.

Then sign the PDF — two ways:

iOS Markup (free, built in): open the PDF, tap the pencil (Markup) icon → + → Signature, draw one, drag it into place, tap Done. Good for a one-off. The catch is the same as always — it’s a raw finger-drawing, and dates and initials are manual text boxes you nudge around by hand.
A signature app (the repeat route): open the PDF, tap Share → Signed. Your saved signature, initials and an auto-filled date are one tap each. You get back a clean, flattened PDF and share it straight back into your reply. In Signed you create the signature once — draw it, type your name in a real handwriting style, or let AI generate one — and it looks identical on every document after that.

The privacy note: the big enterprise e-sign services upload your document to their cloud. For simply signing and returning a file you received, you don’t need that — Signed is local-first, so the document never leaves your phone.

Which should you pick?

Casual, low-stakes .docx you just need something on → insert a transparent PNG in Word. Done.
Anything you’re sending back to someone official → export to PDF first, then sign the PDF. It won’t shift, and it looks finished.
You do this more than occasionally → set up a reusable signature once so every future document is a ten-second job.

One honest caveat: for high-stakes legal agreements, a signature image on a page may not be the entire requirement — check what’s actually expected for that specific document before you rely on it. Signed is a signing tool, not legal advice.